Mechanical Properties Of Woven Composites Research Articles

A deep learning approach for predicting the architecture of 3D textile fabrics

In this paper, a deep learning approach to 3D textile geometry simulations is presented. Two different network architectures with convolutional and recurrent properties are explored. The deep neural networks were trained to generate a fully compacted 3D textile unit cell based on the weave initial architecture. The AI training was conducted on a set of precomputed weaving case studies generated by digital element based weaving simulation software. The proposed strategy demonstrated effectiveness in estimation of 3D textile architectures. The designed system was able to operate within 10% error for stiffness properties prediction. The main benefit of the proposed approach over conventional modelling is its computational efficiency. Rapid weaving simulations provide an opportunity to explore the effects of different yarn architectures, matrix materials, and manufacturing techniques on the mechanical properties of woven composites, leading to a better understanding of their behaviour and their potential for use in new applications.

Multiscale Study of the Effect of Fiber Twist Angle and Interface on the Viscoelasticity of 2D Woven Composites.

Time and temperature affect the viscoelasticity of woven composites, and thus affect their long-term mechanical properties. We develop a multiscale method considering fiber twist angle and interfaces to predict viscoelasticity. The multiscale approach is based on homogenization theory and the time-temperature superposition principle (TTSP). It is carried out in two steps. Firstly, the effective viscoelasticity properties of yarn are calculated using microscale homogenization; yarn comprises elastic fibers, interface, and a viscoelastic matrix. Subsequently, the effective viscoelasticity properties of woven composites are computed by mesoscale homogenization; it consists of homogenized viscoelastic yarns and matrix. Moreover, the multiscale method is verified using the Mechanics of Structure genome (MSG) consequence. Finally, the effect of temperature, fiber twist angle, fiber array, and coating on either the yarn's effective relaxation stiffness or the relaxation moduli of the woven composite is investigated. The results show that increased temperature shortens the relaxation time of viscoelastic woven composites, and fiber twist angle affects tensors in the relaxation stiffness matrix of the yarn; the coating affects the overall mechanical properties of woven composites as well.

Investigation of the effects of nanoparticle reinforcement on the mechanical properties of woven composites

AbstractNanoparticles are used in many areas related to composite materials. Recently, the importance of nanoparticle‐reinforced materials in advanced technology has been gradually increasing. In this study, epoxy reinforced with various nanoparticles, and neat epoxy were used to produce woven composites. The fatigue behaviors of woven composites reinforced with various nanoparticles under tension‐compression fatigue loads were investigated. The tensile and fatigue strengths of woven composites enhanced with nanoparticles were compared with woven composites without nanoparticles. Tensile tests showed that the woven composites reinforced with nanoparticles were damaged at high loads. Fatigue tests revealed that the woven composites reinforced with nanoparticles exhibited high cycle numbers. Adding 0.5%, 1%, and %3 nano‐CuO to epoxy increased the cycle numbers of the woven composites by 25%, 67%, and 75% respectively at 60% load level. The failure mechanisms of woven type composite materials were investigated by scanning electron microscopy (SEM). Fiber fractures and delamination damages of samples were observed.

Effects of the addition of carbon nanofibers on mechanical properties of woven glass/epoxy composites with different weave patterns

The harness and the weave style are among the most important properties of woven fabrics. Most of the previous studies utilized woven fabrics with specific harnesses to explore the effects of nanoparticles on woven composites. Therefore, an experimental study was conducted to examine the impact of three weave patterns, namely plain, 5-harness satin, and 8-harness satin, on the mechanical properties of woven composites under tensile and shear loads. Subsequently, the effect of applying carbon nanofibers (CNFs) to epoxy resin reinforced with woven glass fibers with various harnesses was studied. The experimental results were evaluated statistically, indicating that using CNFs differently affects composite properties with various fabric harnesses. The addition of 0.5 wt.% CNFs to woven composites with varied harnesses enhanced the tensile strength by 19.2%–22.9% and the tensile fracture strain by 12.9%–13.8%, respectively. However, the elastic tensile modulus of woven composites was not increased. A further increase in the CNFs weight fraction from 0.5 wt.% did not improve the tensile properties. The addition of 0.5 wt.%, 1.0 wt.% and 1.5 wt.% CNFs increased the shear strength up to 30.6% and the shear modulus up to 18.7%, respectively. The results showed that the addition of CNFs more significantly affected the shear than the tensile properties. It was also revealed that employing a proper weight fraction of CNFs and a proper fabric harness significantly improves the mechanical properties of woven composites. Finally, an empirical model was developed to predict the strength and elastic modulus of woven composites with different harnesses and CNF weight fractions.

Multiscale modelling of thermoplastic woven fabric composites: From micromechanics to mesomechanics

The mechanical properties of woven composites can be predicted by using a multiscale modelling approach. The starting point to its application is the microscale (the level of fibres, matrix and interfaces), that allows the computation of the homogenised behaviour of the yarn. The aim of this work was to predict the yarn-level behaviour of a thermoplastic-based woven composite in order to allow the formulation of a representative constitutive model that can be used to predict ply properties at the mesoscale. To accomplish this purpose, an in situ characterisation of the microconstituents was carried out. This served to generate inputs for three different representative volume element (RVE) models that allowed predicting the yarn longitudinal, transverse and shear responses. These mechanical characteristics allowed the determination of homogenised yarn constitutive behaviour which was found to be characterised by significant non-linearity until failure, specially in transverse and shear directions.

Predicting the effect of voids on mechanical properties of woven composites

An accurate yet easy to use methodology for determining the effective mechanical properties of woven fabric reinforced composites is presented. The approach involves generating a representative unit cell geometry based on randomly selected 2D orthogonal slices from a 3D X-ray micro-tomographic scan. Thereafter, the finite element mesh is generated from this geometry. Analytical and statistical micromechanics equations are then used to calculate effective input material properties for the yarn and resin regions within the FE mesh. These analytical expressions account for the effect of resin volume fraction within the yarn (due to infiltration during curing) as well as the presence of voids within the composite. The unit cell model is then used to evaluate the effective properties of the composite.

Finite element analysis of mechanical properties of woven composites through a micromechanics model

Abstract In a woven fabric composite, arrangement and behavior of the fibers contained in the yarn and the yarns themselves lead to an intricate deformation mechanism. The current research, therefore, intends to propose a simplified mathematical micromechanics model for calculating mechanical properties of the plain weave composite using finite element analysis (FEA). A repetitive volume element (RVE) cell approach has been adopted for properties evaluation of plain weave composites. The FEA allows the modeling and portrayal of fabrics by taking into account various geometric parameters such as the yarn undulation, the probability of existence of consonances in a unit cell and interaction between warp and fill tows. These factors help in generating a mesh close to the actual fabric/composite. Additionally, a technique to represent the internal layout of composite structure employing actual dimensions of yarn geometry using conventional measurement devices, rather than using the demanding method of obtaining measurements from photomicrographs of sectioned laminates, is also proposed. The geometric symmetries as reported in the available literature were also incorporated during the model formulation. The theory of comparative displacements was then used to construe these symmetries into appropriate mechanical terms. Consequently, this leads to the formulation of boundary conditions for the RVE. The proposed finite element micromechanics model is different from the existing models in a way that it defines the yarn cross-sectional path based upon computational fluid dynamics technique rather than conventionally obtained photomicrographic results or the proposed sinusoidal paths by various researchers. Experiments were then performed on the laminates used for obtaining the geometric parameters with the aim of supporting the validity of the suggested model. The results of computational analysis were found to be in good agreement with the outcomes of experimental investigation.

Three-dimensional exact modeling of geometric and mechanical properties of woven composites

ABSTRACT A formulation for the prediction of the in uence of various parameters on the elastic moduli of three-dimensional (3D) orthogonally woven composites has been given. These parameters can be classified into different groups according to their properties, such as input design and material parameters, structural parameters etc. Some, by their nature, can be well controlled during the design and manufacture of the composite. The composite is assumed to be homogeneous and orthotropic macroscopically. With a selected representative unit cell and the stiffness model developed by author in 2000, the in uence of all of these parameters can be determined. Results showing the in uence of the main design geometric parameters are presented. They demonstrate that an optimal design is possible for the through-the-thickness stiffness of the composites. The methodology used can be generalized to predict the behavior of other kinds of 3D woven structures.

Integrated micro/macro-mechanical model of woven fabric composites under large deformation

Thermoforming of woven composite panels generally involves significant in-plane shear deformation, and induces additional anisotropy into the composites. In our previous paper, a new constitutive model for macro-mechanically characterizing the non-orthogonal material behavior under large deformation was proposed. In the present work, we develop an integrated micro- and macro-constitutive model to predict the mechanical properties of woven composites during large deformation based on the microstructure of composites, i.e., the dimensions of fibers, yarns and unit cell, the material properties of composite constituents, as well as the orientation of yarns. The modeling strategy starts with a geometrical description of the yarn and the unit cell during a trellising shear deformation. Following this, a mechanistic analysis on a unit cell has been conducted to determine the equivalent shear properties of woven composites used in our non-orthogonal model. Meanwhile, a simple and conventional analytical technique is applied to predict the tensile properties of woven composites. The proposed integrated micro/macro-model shows excellent agreement with the experimental data and the 3D finite element results. Finally, a parametric study is performed using the presented models to investigate the effects of major geometrical parameters and material properties of the constituents on the shear properties of plain weave composites.

Geometric parameters and their influence on the mechanical properties of woven composites

Geometric parameters and their influence on the mechanical properties of woven composites

Influence of Damage on Mechanical Properties of Woven Composites at Low Temperatures

Large quantities of nonmetallic woven composites will be used in magnetic fusion energy (MFE) structures at low temperatures. Understanding variations in mechanical properties will provide useful information to the MFE designer. Here we study the influence of crack formation, residual thermal stresses, and weave curvature on the mechanical performance of G10-CR glass/epoxy laminates. Improved material performance is suggested by studying the load-deformation response of a unit cell of plain weave. A generalized plane strain finite-element model was used to predict crack-tip singularities and redistribution of stresses within a thin slice of warp-fill fiber bundles. The model predicts that warp curvature and thermal stresses at low temperatures are beneficial in reducing crack-tip singularities of fill cracks. The opposite is true for stiffness, which is decreased both by curvature and fill cracks. Results of this model provide the designer a tradeoff between stiffness and strength.